1. Field of the Invention
The present invention relates to a radio receiver.
2. Description of the Related Art
A radio receiver of a synthesizer type in general has a presetting function of receive frequencies. For example, the following steps are taken:
1. making a channel selection of a frequency "15290 kHz" by manual operation, and
2. pushing "1" key out of the numeric keys while depressing a "register key". Then, by pushing only the "1" key thereafter, the frequency 15290 kHz can be selected.
Therefore, by using such presetting function at the time of channel selection, a desired broadcasting station can be simply selected by a single touch operation.
In the shortwave broadcasting, since the receive conditions vary with the time of the year or day, such popular broadcasting stations as VOA and BBC are broadcasting their programs at a plurality of different frequencies; they are changing their transmit frequencies varying with the time of the year or day.
Accordingly, in receiving such shortwave broadcasting, it becomes necessary to change the receive frequency according to the receive conditions, depending on the time of the year or day.
Even in the intermediate-frequency broadcasting, some broadcasting stations are broadcasting the same program in different frequencies for the areas where radio wave conditions are not good by using satellite stations to thereby improve the receive conditions in such areas. Further, since the intermediate-frequency broadcasting cannot cover a wide service area, when for example a radio receiver is moved from Tokyo to Osaka, the frequency for receiving the same program becomes quite different.
Thus, a large number of frequencies are used for the radio broadcasting. If all of the frequencies for many kinds of broadcasting have to be preset as described above, it becomes necessary to provide a large number of keys. Then, the control panel of the radio receiver will become full of keys. In addition, it must be remembered then which key was preset to which frequency, and thereby the merit of the presetting is impaired considerably.
Such things not only impair operability but also adversely affect the external appearance of the radio receiver.